On Mon, May 16, 2016 at 3:56 PM, Alan Hodgson <ahodg...@lists.simkin.ca> wrote:
> On Monday, May 16, 2016 03:41:23 PM David G. Johnston wrote: > > I have a psql script that obtains data via the \copy command and loads it > > into a temporary table. Additional work is performed possibly generating > > additional temporary tables but never any "real" tables. Then the script > > outputs, either to stdout or via \copy, the results. > > > > Does it matter whether I issue a ROLLBACK or a COMMIT at the of the > > transaction? More basically: does it matter whether I issue a BEGIN? > > > > The script runs on Ubuntu inside a bash shell's heredoc. > > > > Some things will complete faster if you use BEGIN to start, as PostgreSQL > will > otherwise issue an implicit BEGIN and COMMIT before and after every > statement. > > Non-zero but minimal compared to the I/O hit. The slightly more meaningful savings would be in lesser consumption of transaction id values. Though both would probably only matter at scale. > If you don't need anything saved at the end it probably doesn't matter if > you > use ROLLBACK or COMMIT. > Yeah, without the front end of this being optimized for once you get to the end you've already consumed the relevant resources and I suspect that as far at the catalogs go those temp tables are just as good as rolledback on session end. David J.
